I keep my Bookmarks Sidebar open. It works properly for a few minutes and then it doesn't. The behavior it shows is as follows. 1. It quits scrolling. I have to click the web page and go back to the sidebar to scroll again. 2. It scrambles the bookmarks when I click one. 3. When I click one bookmark it opens some other one. Basically it acts crazy. The one fix I have found is when it is acting up and I close and reopen the sidebar it starts working properly again for a while. Then the problems repeats until I close and reopen the sidebar. Late 2011 13" MacBook Pro MacOS 10.13.67 I forgot to mention this is happening on two (2) late 2011 MacBook Pros both with MacOS 10.13.6 and one has a clean install about a week ago.

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration or userChrome.css is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

I was using the LIGHT theme. I went to the DEFAULT theme and my Bookmarks Sidebar is working normally. Thanks a million.